1. Field of the Invention
The present invention generally relates to ventilation systems for vehicles and, more particularly, to a heating and air-conditioning system for berths and cabs of a plurality of types of vehicles.
2. Background Art
Cabs of road transport vehicles are often equipped with sleeper berths, which consist of resting accommodations for the driver. Road transport vehicles often travel over long distances, whereby sleeper berths are provided for the driver to recuperate. Similarly, recreational vehicles have self-contained living berths for the vehicle occupants.
In order to maintain suitable climate conditions, sleeper berths and living berths are typically provided with HVAC systems (i.e., heating, ventilating and air-conditioning systems) that treat, heat and/or cool the air that is fed to the berths/cabs, so as to provide adequate resting conditions for its occupants.
Berths, and cabs of specific types of vehicle (e.g., cranes, service vehicles, buses, cars and other passenger vehicles), often accommodate occupants while the engine is turned off as well as when the vehicle is in operation. Accordingly, the actuation of such ventilation systems is of concern, in that the engine may be turned off while the HVAC systems has to work, whereby the alternator associated with the engine does not maintain the voltage level of the electrical systems of these vehicles. In various instances, no external power supply is available, whereby some ventilation systems of berths and cabs are powered by the electrical system of the vehicle. In order to avoid the discharge of the batteries of the electrical systems while heating or cooling berths or cabs, vehicle engines are kept on so as to keep, for instance, the alternator in a charging mode for the electrical system.
Accordingly, some uses of such ventilation systems involve vehicle fuel consumption, either by requiring that the engine be turned on to operate, or by affecting the performance of the vehicle by being mechanically related to the engine. This results in combustion by-product emissions. Therefore, not only are such ventilation systems costly to operate because of fuel consumption, they also have a negative effect on the environment.